Anchoring washer for an EME protection cap system

ABSTRACT

A cap system for enclosing a metallic fastener assembly extending through a structure includes a first securement mechanism positioned about a periphery of a washer of the metallic fastener assembly wherein the first securement mechanism includes threads. The cap system further includes a cap member including a sidewall having an inner surface which defines a cavity dimensioned to receive the washer and defines a second securement mechanism complementary configured to engage the first securement mechanism positioned about the periphery of the washer. An end of the sidewall of the cap member defines an opening which provides the washer to have access into the cavity.

FIELD

This disclosure relates to an electrical insulation cap assembly forinsulating metallic fasteners from transmitting current or sparks intothe vicinity of the location of the metallic fastener assembly with theoccurrence of electromagnetic effect (“EME”) or lightning strike eventand more particularly for electrical insulating containment caps whichenclose a metallic threaded fastener.

BACKGROUND

Electrically insulated sealant and containment caps have been used tocover an end portion of a metallic fastener assembly which includes anut and a threaded end portion of a stud which extends beyond the nutand which may include one or more washers. The sealant caps electricallyinsulate the end portion of the metallic fastener assembly so as toelectrically isolate and contain the end portion of the metallicfastener assembly from critical surroundings of the metallic fastenerassembly such as within a vicinity of a fuel tank or sensitiveelectronic equipment within an aircraft. Electrically isolating andcontaining the end portion of the metallic fastener assembly preventsunwanted sparks or electrical current transmissions entering into suchimportant surroundings upon an EME or lightning strike event.

The insulation and containment caps are made from sealant material suchas for example a thermoset plastic. The caps are also filled with aliquid form of sealant material. Once the cap is filled with liquidsealant, the cap is positioned over the end portion of the metallicfastener assembly enclosing the end portion of the metallic fastenerassembly within the cap and a surface of a structure from which the endportion of the metallic fastener assembly extends. At times sealant isexpelled from the cap being over filled with sealant. This expelling ofsealant can also occur by way of a sufficient amount of sealant beingpresent such that expelling of some sealant from the cap can occur whichindicates an adequate amount of sealant has been used. The expelledsealant in either occurrence must then be smoothed out about the cap toensure proper sealing of the cap and for aesthetics. This smoothing outprocess is tedious and time consuming.

The cap also requires being held in place for a time period so as tomaintain the cap's position to prevent an occurrence of the capexperiencing slumping or lifting off of the surface of a structure fromwhich the end portion of the metallic fastener assembly extends duringthe curing of the sealant. The cap-to-structure joints are subject tohigh quality standards and often require rework.

There is a need to reduce the time to install EME or lightning strikeevent protective caps enclosing end portions of metallic fastenerassemblies in high criticality areas such as in the proximity of fueltanks or sensitive electronic equipment of an aircraft. In additionthere is a need to have a reliable securement mechanism for securing thecaps to the end portions of the metallic fasteners.

SUMMARY

A cap system for enclosing a metallic fastener assembly extendingthrough a structure including a first securement mechanism positionedabout a periphery of a washer of the metallic fastener assembly whereinthe first securement mechanism includes threads. A cap member includes asidewall having an inner surface which defines a cavity dimensioned toreceive the washer and defines a second securement mechanismcomplementary configured to engage the first securement mechanismpositioned about the periphery of the washer. The cap system furtherincludes an end of the sidewall of the cap member defines an openingwhich provides the washer to have access into the cavity.

A cap system for enclosing a metallic fastener assembly extendingthrough a structure including a first securement mechanism positionedabout a periphery of a washer of the metallic fastener assembly whereinthe first securement mechanism includes a first tab member extending ina direction transverse to a plane of a surface of the washer and asecond tab member extending in a direction transverse to the plane ofthe surface of the washer spaced apart from the first tab member aboutthe periphery of the washer. The cap system further includes a capmember including a sidewall having an inner surface which defines acavity dimensioned to receive the washer and defines a second securementmechanism complementary configured to engage the first securementmechanism positioned about the periphery of the washer. The cap systemfurther includes an end of the sidewall of the cap member defines anopening which provides the washer to have access into the cavity.

The features, functions, and advantages that have been discussed can beachieved independently in various embodiments or may be combined in yetother embodiments further details of which can be seen with reference tothe following description and drawings.

BRIEF SUMMARY OF THE DRAWINGS

FIG. 1 is an exploded perspective view of a first embodiment of a capsystem for enclosing an end portion of a metallic fastener assemblyextending from a structure;

FIG. 2 is a cross section view along line 2-2 of FIG. 1 of the firstembodiment of the cap system assembled;

FIG. 3 is a perspective cross section view of employment of the firstembodiment of the cap system of FIG. 1 utilizing three different exampleconfigurations of the metallic fastener assembly;

FIG. 4 is an enlarged bottom perspective view of the first embodiment ofthe cap member of FIG. 1 showing a first example of the end of the capmember;

FIG. 5 is an exploded perspective view of a second embodiment of the capsystem for enclosing an end portion of the metallic fastener assemblyextending from the structure;

FIG. 6 is a cross section view along line 6-6 of FIG. 5 of the secondembodiment of the cap system assembled;

FIG. 7 is a perspective cross section view of employment of the secondembodiment of the cap system of FIG. 5 utilizing three different exampleconfigurations of the metallic fastener assembly;

FIG. 8 is an enlarged bottom perspective view of the cap member of FIG.5 showing a second example of the end of the cap member; and

FIG. 9 is an enlarged bottom perspective schematic view of a cap membershowing a third example of the end of the cap member.

DESCRIPTION

A cap system described herein will be employed to enclose an end portionof a metallic fastener assembly which is secured to and projects from astructure, in this example, a structure positioned within an aircraft.The cap system has a cap member. The cap member is to be positioned overand enclose the end portion of the metallic fastener assembly whichextends from the structure and the cap member secures to the metallicfastener assembly. With an end of the cap member positioned abutting asurface of the structure, the end portion of the metallic fastenerassembly is enclosed within the confines of the cap member and a surfaceof the structure. With positioning the cap member to enclose the endportion of the metallic fastener assembly the cap member also secures tothe metallic fastener assembly.

The cap is constructed of a nonconductive material such as a polymer,thermoset or of other nonconductive material and a nonconductive sealantmaterial may be additionally used in association with the cap member tofurther electrically isolate the end portion of the metallic fastenerassembly from the surrounding vicinity of the metallic fastener assemblypositioned outside of the cap member. Surrounding vicinities within anaircraft which would need electrical transmission isolation from ametallic fastener assembly include areas such as a fuel tank, areaswhich contain sensitive electronic equipment or areas which couldotherwise be adversely affected by a transmission from an EME orlightning strike event such as experienced by an aircraft.

A metallic fastener assembly, in this example, two configurations couldinclude a threaded stud which includes at one end a nut or could includea threaded bolt which at one end includes a head. In employing a firstconfiguration of the metallic fastener assembly a threaded stud isextended through the structure(s) and a nut is positioned onto thethreaded stud on one side of the structure(s) to which the metallicfastener assembly is to be secured. A nut member with threads compatibleto the threads of the threaded stud is engaged to the threaded stud onan opposing second side of the structure(s), a side to which the capsystem to be described herein will be positioned. At least one washer ispositioned between the nut member and the structure(s) wherein the capsystem includes a portion of the at least one washer which engages a capmember of the cap system and the cap member encloses the nut member, theat least one washer and the threaded stud projecting from thestructure(s).

In a second configuration of the metallic fastener assembly a threadedbolt is extended through the structure(s) with the head of the threadedbolt positioned on one side of a structure(s) to which the metallicfastener assembly is to be secured. A nut member with threads compatibleto the threads of the threaded bolt is engaged onto the bolt on anopposing second side of the structure(s), a side to which the cap systemto be described herein will be positioned. At least one washer ispositioned between the nut member and the structure(s) wherein the capsystem includes a portion of the at least one washer which engages a capmember of the cap system and the cap member encloses the nut member, theat least one washer and the threaded bolt projecting from thestructure(s).

In a third configuration of the metallic fastener assembly a threadedbolt is extended through the structure(s) with the head of the threadedbolt positioned on the side of the structure(s) in which the cap systemto be described herein will be positioned. A nut with compatible threadsis secured to the threaded bolt on an opposite side of the structure(s).At least one washer is positioned between the head and the structure(s)wherein the cap system includes a portion of the at least one washerwhich engages a cap member of the cap system and the cap member enclosesthe head and the at least one washer.

In the first and second configuration of the metallic fastener assembly,with the tightening of the nut member on the threaded stud or on thethreaded bolt in a direction toward the structure(s) a compressive forceis applied to the structure(s) positioned between the nut (not shown)and the nut member with respect to the threaded stud or the compressiveforce is applied to the structure(s) positioned between the head (notshown) and the nut member with respect to the threaded bolt. With thecompressive force applied with the nut member on one of a threaded studor threaded bolt of the metallic fastener assembly, the metallicfastener assembly is in a secured position with respect to thestructure(s). In the third configuration of the metallic fastenerassembly, with tightening of the head of the threaded bolt in adirection toward the structure(s) a compressive force is applied to thestructure(s) positioned between the head and the nut secured to thethreaded bolt positioned on the other side of the structure(s). With thecompressive force applied the threaded fastener assembly in this thirdconfiguration, the metallic fastener assembly is in a secured positionwith respect to the structure(s).

With the metallic fastener assembly in a secured position with respectto the structure(s) and with a cap member of the cap system enclosing anend portion of the metallic fastener assembly positioned projecting froma side of the structure(s) the cap member of the cap system at the sametime secures to a portion of at least one washer of the cap system, andthe cap member will be secured to the metallic fastener assembly andpositioned against the structure.

In referring to FIG. 1, in this example, an end portion 10 of metallicfastener assembly 11 is shown projecting from surface 12 of structure14. Structure 14 is shown schematically wherein structure 14 may includeone or more components to which metallic fastener assembly 11 issecured. Metallic fastener assembly 11 in this example includes threadedstud or bolt 16 which has a nut (not shown) or head (not shown)positioned beneath structure 14. Threaded stud or threaded bolt 16 hasthreads 18, metallic fastener assembly 11 includes, in this example,washer 20 which is positioned surrounding threaded stud or threaded bolt16 and abuts surface 12 of structure 14. Metallic fastener assembly 11further includes washer 21 positioned on washer 20. Metallic fastenerassembly 11 also includes nut member 22 which has threads 24 positionedwithin nut member 22 which are compatible to engage with threads 18 ofthreaded stud or threaded bolt 16 wherein threaded stud or threaded bolt16 extends through structure 14. Threads 24 of nut member 22 can engagethreads 18 of threaded stud or threaded bolt 16 and be tightened downresulting in exerting a compressive force with respect to structure 14.With structure 14 positioned between nut member 22 and nut (not shown)or head (not shown) of threaded stud or threaded bolt 16, respectively,of metallic fastener assembly 11, metallic fastener assembly 11 obtainsa secured position with respect to structure 14. In this example, washer21 is positioned between nut member 22 and washer 20.

In FIG. 1, first embodiment of cap system 26A is shown enclosingmetallic fastener assembly 11 extending through structure 14. Cap system26A has cap member 28A. As mentioned earlier cap member 28A will beconstructed of a nonconductive material such as one of a polymer,thermoset or other nonconductive materials. Cap member 28A has sidewall29A having inner surface 30A, as seen in FIGS. 2-4. First securementmechanism 34A of cap system 26A, as seen in FIG. 1, is positioned aboutperiphery 36A of washer 21 of metallic fastener assembly 11. Cap member28A includes sidewall 29A having inner surface 30A which defines cavity32A dimensioned to receive washer 21 and defines second securementmechanism 38A, as seen in FIG. 4, which is complementary configured toengage first securement mechanism 34A positioned about periphery 36A ofwasher 21. End 40A of sidewall 29A of cap member 28A defines opening 42Awhich provides in this example washers 20, 21, nut member 22 includingthreaded portion of one of threaded stud or threaded bolt 16 whichprojects from structure 14 to have access into cavity 32A.

As seen in FIG. 1, first securement mechanism 34A includes threads 44Apositioned on washer 21. Nut member 22 includes ridge members 46A, inthis example, which are configured to receive and engage a standardsocket wrench for tightening nut member onto washers 20 and 21 andsecuring washers 20 and 21 against structure 14.

Second securement mechanism 38A includes threads 50A defined by innersurface 30A of sidewall 29A of cap member 28A, as seen in FIG. 4.Threads 50A extend about inner surface 30A of cap member 28A and extendin a direction D away from end 40A of sidewall 29A of cap member 28A. Aswill be discussed further below, with nut member 22 and threaded stud orthreaded bolt 16 in a secured position with respect to structure 14 andwith threads 50A engaging threads 44A of washer 21, end 40A of sidewall29A of cap member 28A is positioned against structure 14 enclosing endportion 10 of metallic fastener assembly 11 and cap member 28A issecured to washer 21 of metallic fastener assembly 11. With threads 50Aextending in direction D, threads 50A extend toward higher elevationswith respect to surface 12 with end 40A abutting surface 12 as shown inFIG. 3. Threads 50A can accommodate and engage threads 44A of washer 21as threads 44A may differ in elevation position relative to surface 12as will be shown and discussed with respect to FIG. 3, thereby ensuringsecurement of cap member 26A to end portion 10 of metallic fastenerassembly 11 and end 40A abutting surface 12 enclosing end portion 10.

In FIG. 3, first example 52A of end portion 10 of metallic fastenerassembly 11 extending above surface 12 of structure 14 is seen whereinfirst embodiment of cap system 26A is shown enclosing of end portion 10and securing to end portion 10 of metallic fastener assembly 11. Infirst example 52A, nut member 22 is secured to threads 18 of threadedstud or threaded bolt 16 and nut member 22 directly abuts washer 21which in turn abuts surface 12. Threads 44A of washer 21 are engaged tothreads 50A wherein threads 44A are positioned above surface 12 at anelevation profile lesser than that of threads 44A in second example52A1.

In second example 52A1, in FIG. 3, first embodiment of cap system 26Aencloses and secures to end portion 10 of metallic fastener assembly 11which is positioned extending in this example above surface 12. Insecond example 52A1, nut member 22 is secured to threads 18 of threadedstud or threaded bolt 16 and nut member 22 is positioned on washer 21which positions threads 44A of washer 21 which engage to threads 50A ofcap member 28A. Threads 44A are positioned above surface 12 at a higherelevation profile than that of threads 44A of washer 21 of first example52A. Threads 50A of cap member 28A extend in direction D as seen in FIG.4 permitting threads 44A of washer 21 to be engaged to threads 50A inboth the first example 52A and second example 52A1 with end 40A ofsidewall 29A of cap member 28A abutting surface 12 of structure 14. As aresult, cap member 28A encloses end portion 10 of metallic fastenerassembly 11 and secures to end portion 10 of metallic fastener assembly11 with the engagement of threads 44A of washer 21 with threads 50A ofcap member 28A regardless of the difference in elevation profile ofthreads 44A with respect to surface 12, as seen in first example 52A and52A1.

Thus, with an installer having tightened nut member 22, of the first andsecond examples 52A and 52A1 in FIG. 3 with threads 24 compatible withthreads 18 of threaded stud or threaded bolt 16, into a secured positionrelative to structure 14, the installer can then position firstembodiment of cap 28A to have threads 44A of washer 21 engage threads50A of cap member 28A. The installer can then turn and tighten capmember 28A, with threads 44A and 50A engaged, until end 40A ispositioned against or abuts surface 12. Cap member 28A is then securedto surface 12 and secured to metallic fastener assembly 11 enclosing endportion 10 of metallic fastener assembly 11. As explained above, withthreads 50A extending in direction D, threads 44A of washer 21positioned at different elevation profiles above surface 12 can engageand reliably secure to threads 50A thereby securing cap member 28A toend portion 10 of metallic fastener assembly 11 and with end 40Aabutting surface 12 cap member 28A securely encloses end portion 10 ofmetallic fastener assembly 11.

In the third example 52A2, as seen in FIG. 3, metallic fastener assembly11 includes head 53 of a threaded bolt member 16 wherein head 53 ispositioned in overlying relationship to washer 21. Head 53 is positionedin a secure relationship with respect to structure 14 with a nut (notshown) positioned below structure 14 secured to threads 18 of threadedbolt 16. Washer 21 is positioned between head 53 and structure 14 andwith threads 44A positioned about periphery 36A of washer 21 engagingthreads 50A defined by inner surface 30A of cap member 28A, end 40A, asseen in FIG. 4, of cap member 28A is positioned against structure 14.

In this third example 52A2, the installer having tightened head 53 ontothreads 18 of threaded bolt 16 into a secured position relative tostructure 14 with nut (not shown) positioned on threaded bolt 16positioned on opposite side of structure 14 than head 53, the installercan then position first embodiment of cap 28A to have threads 44A ofwasher 21 engage threads 50A of cap member 28A. The installer can thenturn and tighten cap member 28A, with threads 44A and 50A engaged, untilend 40A abuts surface 12. Cap member 28A is then secured to surface 12and secured to metallic fastener assembly 11 enclosing end portion 10 ofmetallic fastener assembly 11. As explained above, with threads 50Aextending in direction D, threads 44A of washer 21 positioned atdifferent elevation profiles, based on for example an addition of awasher, above surface 12 threads 44A can engage and reliably secure tothreads 50A thereby securing cap member 28A to end portion 10 ofmetallic fastener assembly 11 and with end 40A abutting surface 12, capmember 28A securely encloses end portion 10 of metallic fastenerassembly 11.

In referring to FIG. 5, second embodiment of cap system 26B is shownenclosing metallic fastener assembly 11 extending through structure 14.Cap system 26B has cap member 28B. As mentioned earlier cap member 28Bwill be constructed of a nonconductive material such as one of apolymer, thermoset or other nonconductive material and will be moreflexible of a material than a metal construction of the metallicfastener assembly 11 including the portion of the washer 21′ or firstsecurement mechanism 34B. Cap member 28B has sidewall 29B having aninner surface 30B, as seen in FIGS. 6-8. First securement mechanism 34Bof cap system 26B, as seen in FIG. 5, is positioned about periphery 36Bof washer 21 of metallic fastener assembly 11. Cap member 28B includessidewall 29B having an inner surface 30A which defines cavity 32Bdimensioned to receive washer 21′ and defines second securementmechanism 38B, which is seen in FIG. 8, which is complementaryconfigured to engage first securement mechanism 34B positioned aboutperiphery 36B of washer 21. End 40B of sidewall 29B of cap member 28Bdefines opening 42B which provides in this example washers 20, 21′, nutmember 22 and threaded portion of one of threaded stud or threaded bolt16 which projects from structure 14 to have access into cavity 21BAsseen in FIG. 5.

First securement mechanism 34B includes first tab member 45B extendingin a direction D′ transverse to a plane P of surface 49B of washer 21′and second tab member 47B extending in the direction D′ transverse tothe plane P of the surface 49B of washer 21′ spaced apart from first tabmember 45B about periphery 36B of washer 21′. Each of first and secondtab members 45B and 47B include plurality of grooves 51B. Nut member 22includes plurality of ridges 46B which are compatible with a standardsocket wrench so as to receive and engage a standard socket wrench fortightening nut member 22 onto washers 20 and 21′ against structure 14.Second securement mechanism 38B includes plurality of teeth 50B definedby inner surface 30B of sidewall 29B of cap member 28B, as seen in FIG.8. Plurality of teeth 50B extend about at least a portion of innersurface 30B of sidewall 29B of cap member 28B. Plurality of teeth 50Bextend in a direction D away from end 40B of sidewall 29B of cap member28B. As will be discussed further below, with nut member 22 and threadedstud or threaded bolt 16 in a secured position in relationship tostructure 14 and with plurality of teeth 50B engaging at least a portionof continuous threads 44B of washer 21, end 40B is positioned againststructure 14 enclosing end portion 10 of metallic fastener assembly 11.Plurality of teeth 50B can be extended in direction D away from end 40Bof cap member 28B if needed. Plurality of teeth 50B can extend (notshown) toward higher elevations above surface 12 of structure 14 whichcan accommodate different positions of elevation profile of plurality ofgrooves 51B with end 40B in abutting relationship with surface 12 ofstructure 14. As a result, plurality of teeth 50B can accommodate andengage plurality of grooves 51B of washer 21′ at different elevations ofposition of grooves 51B with respect to structure 14 if needed.Plurality of teeth 50B as mentioned earlier are constructed of amaterial more flexible than the material which constructs the pluralityof grooves 51B. In this instance, as the installer pushes downwardly ortoward structure 14 plurality of teeth 50B flex as they contact grooves51B. With end 40B positioned against structure 14 plurality of teeth 50Bin alignment with plurality of grooves 51B, plurality of teeth 50B flexback and engage plurality of grooves 51B.

With installer inserting first and second tab members 45B and 47B intocap member 28B, first and second tab members 45B and 47B respectivelyare aligned with first slot 55B and second slot 57B, respectively asseen in FIG. 8 defined by cap member 28B. This alignment of first andsecond tab members 45B and 47B with first and second slots 55B and 57Brespectively, provides the installer easy alignment of plurality ofgrooves 51B with plurality of teeth 50B and provides resistance ofrotational movement of cap member 28B relative to washer 21′.

In FIG. 7, first example 52B of end portion 10 of metallic fastenerassembly 11 extending in this example above surface 12 of structure 14is seen wherein second embodiment of cap system 26B is shown enclosingof and securing to end portion 10 of metallic fastener assembly 11. Infirst example 52B, nut member 22 is secured to threads 18 of threadedstud or threaded bolt 16 and directly abuts washer 21′ and withplurality of grooves 51B engaged with plurality of teeth 50B, end 40B ispositioned against structure 14.

In second example 52B1, in FIG. 7 second embodiment of cap system 26Bencloses and secures to end portion 10 of metallic fastener assembly 11wherein washer 21′ is positioned in the same position as shown in firstexample 52B however washer 23 is positioned between washer 21′ and nutmember 22. In this example plurality of teeth 51B extend in direction D.However, plurality of teeth 51B can be limited in this example in howfar plurality of teeth 51B extend from end 40B since elevation ofplurality of grooves 51B of first and second tab members 45B and 47Bwith respect to first and second examples 52B and 52B1 are withoutchange. In second example 52B1, nut member 22 is secured to threads 18of threaded stud or threaded bolt 16 and is positioned on washer 23which elevates nut member 22 however, washer 21′ remains on structure 14at the same elevation as seen in first example 52B. Metallic fastenerassembly 11 further includes nut member 22. Nut member 22 has threads 24compatible with threads of one of threads of a threaded stud of themetallic fastener assembly or threads of a threaded bolt 16 of metallicfastener assembly 11, is positioned on one of the threaded stud or thethreaded bolt 16 of metallic fastener assembly 11 in a secured positionwith respect to the structure 14. With washer 21′ positioned between nutmember 22 and structure 14, in this example with washer 23 positionedbetween nut member 22 and washer 21′, with plurality of grooves 51Baligned with plurality of teeth 50B, end 40B of cap member 28B ispositioned against structure 14.

In the third example 52B2, in FIG. 7, head 53 of threaded bolt 16 ispositioned on washer 21′. In this third example of the metallic fastenerassembly 11 head 53 of threaded bolt member 16 is positioned inoverlying relationship to washer 21′ such that with head 53 in a securerelationship with respect to structure 14, with washer 21′ positionedbetween head 53 and structure 14 and with plurality of grooves 51Baligned with plurality of teeth 50B, end 40B of cap member 28B ispositioned against structure 14.

In installing cap member 28B metallic fastener assembly 11 is in thisexample in a secured relationship with respect to structure 14. Theinstaller positions cap member 28B over end portion 10 of metallicfastener assembly 11 and pushes cap member 28B toward structure 14 untilend 40B is positioned against structure 14 and plurality of grooves 51Bare aligned and engaged with plurality of teeth 50B. As a result capmember 28B is secured to metallic fastener assembly 11 and end portion10 of metallic fastener assembly 11 is enclosed and electricallyisolated from electrically sensitive areas of the aircraft.

In installing cap members of the cap system described above,configurations of ends 40A, 40B and 40 as seen in FIGS. 4, 8 and 9, canbe selectively employed to the different embodiments of the cap membersdescribed herein. Three examples of configurations include examples 60,70 and 90 to be discussed in greater detail below. For example, withrespect to ends 40A and 40B, any of the three examples of endconfigurations 60, 70 or 90 can be employed.

In a first example 60 of configuration of an end is shown in FIG. 4 asend 40A. Sidewall 29A of cap member 28A defines groove 92 which extendsabout cap member 28A. First opening 94 defined by and extends throughfirst portion 96 of sidewall 29A of cap member 28A such that firstopening 94 communicates with groove 92. First flow path 98 extendsthrough first portion 96 of sidewall 29A of cap member 28A and intogroove 92 for conveyance of sealant. Second opening 100 defined by andextends through second portion 102 of sidewall 29A of cap member 28Asuch that second opening 100 communicates with groove 92 and secondopening 100 communicates with cavity 32A of cap member 28A such thatsecond flow path 104 extends from groove 92 through second opening 100of sidewall 29A of cap member 28A and into cavity 32A. Once installerhas injected sealant into groove 92 and sealant flows through groove 92and expels into cavity 32A from second opening 100, the sealantcontinues to flow past nut member 22 between ridge members 46A, in thisexample, upwardly into cap member 28A. Third opening 106, as seen inFIGS. 1, 2 and 4, defined by and extends through sidewall 29A of capmember 28A such that third opening 106 provides third flow path 108, asseen in FIG. 4.

In this first example 60, once the installer has secured cap member 28Ato surface 12 of structure 14, the installer will inject a sealantmaterial into first opening 94 having sealant flow in groove 92 aboutcap member 28A. With groove 92 nearly full or full of sealant, sealantbegins to leak from second opening 100. At that point, the installer isstill injecting sealant into first opening 94 and cavity 32A becomesfull of sealant at which point sealant begins to expel from thirdopening 106. At that point installer understands cap member 28A is fullof sealant and stops injecting further sealant. With sealant expellingfrom third opening 106, installer has a confirmation that sealant hasbeen positioned within groove 72 and cavity 32A providing additionalassurance to the installer that end portion 10 of metallic fastenerassembly 11 has been further electrically isolated within cap member28A. This first example configuration provides the installer the abilityto not expel excessive sealant onto surface 12 and reduces the need fortedious and time consuming smoothing out of excess sealant.

In the second example 70, shown in FIG. 8, end 40B of cap member 28Bforms a continuous annular flat surface 62 which will abut surface 12 ofa planar configuration of structure 14 as seen in FIGS. 6 and 7.

Third example 90 of configuration of an end, is shown in FIG. 9 as end40. Sidewall 29 of cap member 28 defines groove 110 which extends aboutcap member 28. First opening 112 defined by and extends through firstportion 114 of sidewall 29 of cap member 28 communicates with groove 110such that a first flow path 116 extends through first opening 112 andinto groove 110 for conveyance of sealant through first opening 112 intogroove 110. Second opening 118, defined by and extends through firstportion 114 of sidewall 29 of cap member 28, is spaced apart about capmember 28 from first opening 112 wherein second opening 118 communicateswith groove 110 such that second flow path 120 extends from groove 110through second opening 118 of cap member 28 for conveyance of sealant.

In this third example 90, once installer has secured cap member 28 tosurface 12 of structure 14, the installer will inject a sealant materialinto first opening 112 having sealant flow in groove 110 about capmember 28 until sealant begins to leak from second opening 118. At thatpoint the installer has a confirmation that sealant has been positionedwithin groove 110 providing additional assurance to the installer thatend portion 40 of metallic fastener assembly 11 has been furtherelectrically isolated within cap member 28. This third example 90configuration provides the installer ability to not expel excessivesealant onto surface 12 and reduces the need for tedious and timeconsuming smoothing out of excess sealant.

While various embodiments have been described above, this disclosure isnot intended to be limited thereto. Variations can be made to thedisclosed embodiments that are still within the scope of the appendedclaims.

What is claimed:
 1. A cap system for enclosing a metallic fastenerassembly extending through a structure, comprising: a first securementmechanism positioned about a periphery of a washer of the metallicfastener assembly wherein the first securement mechanism comprisesthreads; and a cap member comprising: a sidewall having an inner surfacewhich defines a cavity dimensioned to receive the washer and defines asecond securement mechanism which comprises threads defined by the innersurface which extend about the inner surface of the cap member andcomplementary configured to engage the threads of the first securementmechanism positioned about the periphery of the washer; and an end ofthe sidewall of the cap member defines an opening which provides thewasher to have access into the cavity, wherein the threads of the capmember extend in a direction away from the end of the sidewall of thecap member; and a nut member having threads compatible with one of athreaded stud or a threaded bolt of the metallic fastener assembly,wherein the nut member is positioned on the one of the threaded stud orthe threaded bolt of the metallic fastener assembly in a securedposition with respect to the structure with the washer positionedbetween the nut member and the structure.
 2. The cap system of claim 1,wherein with the nut member in a secured position with respect to thestructure, with the washer positioned between the nut member and thestructure, and with the threads positioned about the periphery of thewasher engaging the threads defined by the inner surface of the capmember, the end of the sidewall of the cap member is positioned againstthe structure.
 3. The cap system of claim 1, wherein the end of thesidewall of the cap member comprises a planar surface.
 4. The cap systemof claim 1, wherein the cap member comprises a nonconductive material.5. The cap system of claim 1, wherein the nut member includes ridgemembers.
 6. The cap system of claim 5, wherein the ridge members arespaced apart from one another.
 7. The cap system of claim 6, wherein theridge members are positioned about the nut member for engaging a socketwrench.
 8. The cap system of claim 1, wherein the end of the sidewalldefines a groove which extends about the cap member.
 9. The cap systemof claim 8, wherein: a first opening defined by and extends through afirst portion of the sidewall of the cap member wherein the firstopening communicates with the groove such that a first flow path extendsthrough the first portion of the sidewall of the cap member and into thegroove for conveyance of sealant.
 10. The cap system of claim 9, furtherincluding: a second opening defined by and extends through a secondportion of the sidewall of the cap member wherein the second openingcommunicates with the groove and the second opening communicates withthe cavity of the cap member such that a second flow path extends fromthe groove, through the second opening of the second portion of thesidewall of the cap member and into the cavity; and a third openingdefined by and extends through the sidewall of the cap member whereinthe third opening provides a third flow path from the cavity of the capmember through the third opening of the sidewall of the cap member. 11.The cap system of claim 9, wherein a second opening defined by andextends through the first portion of the sidewall of the cap memberspaced apart about the cap member from the first opening wherein thesecond opening communicates with the groove such that a second flow pathwhich extends from the groove through the second opening defined by thefirst portion of the sidewall of the cap member.
 12. The cap system ofclaim 1, comprises a continuous annular flat surface.
 13. A cap systemfor enclosing a metallic fastener assembly extending through astructure, comprising: a first securement mechanism positioned about aperiphery of a washer of the metallic fastener assembly wherein thefirst securement mechanism comprises threads; and a cap membercomprising: a sidewall having an inner surface which defines a cavitydimensioned to receive the washer and defines a second securementmechanism which comprises threads defined by the inner surface whichextend about the inner surface of the cap member and complementaryconfigured to engage the threads of the first securement mechanismpositioned about the periphery of the washer; and an end of the sidewallof the cap member defines an opening which provides the washer to haveaccess into the cavity, wherein the threads of the cap member extend ina direction away from the end of the sidewall of the cap member; and ahead of a threaded bolt member positioned in overlying relationship tothe washer such that with the head in a secure relationship with respectto the structure, with the washer positioned between the head and thestructure and with the threads positioned about the periphery of thewasher engaging the threads defined by the inner surface of the capmember, the end of the sidewall of the cap member is positioned againstthe structure.
 14. The cap system of claim 13, wherein the cap membercomprises a nonconductive material.
 15. The cap system of claim 13,wherein the end of the sidewall of the cap member defines a groove. 16.The cap system of claim 13, wherein the end of the sidewall of the capmember comprises a continuous annular flat surface.
 17. A cap system forenclosing a metallic fastener assembly extending through a structure,comprising: a first securement mechanism positioned abut a periphery ofa washer of the metallic fastener assembly wherein the first securementmechanism comprises threads; and a cap member comprising: a sidewallhaving an inner surface which defines a cavity dimensioned to receivethe washer and defines a second securement mechanism complementaryconfigured to engage the first securement mechjanism positioned aboutthe periphery of the washer; and an end of the sidewall of the sidewallof the cap member defines an opening which provides the washer to haveaccess into the cavity; wherein the end of the sidewall of the capmember defines a groove which extends about the cap member; a firstopening defined by and extends through a first portion of the sidewallof the cap member wherein the first opening communicates with the groovesuch that a first flow path extends through the first portion of thesidewall of the cap member and into the groove for conveyance ofsealant; a second opening defined by and extends through a secondportion of the sidewall of the cap member wherein the second openingcommunicates with the groove and the second opening communicates withthe cavity of the cap member such that a second flow path extends fromthe groove, through the second opening of the sidewall of the cap memberand into the cavity; and a third opening defined by and extends throughthe sidewall of the cap member wherein the third opening provides athird flow path from the cavity of the cap member through the thirdopening of the sidewall of the cap member.
 18. The cap system of claim17, wherein the cap member comprises a nonconductive material.
 19. Thecap system of claim 17, further includes a nut member having threadscompatible with one of a threaded stud or a threaded bolt of themetallic fastener assembly.
 20. The cap system of claim 19, wherein thenut member comprises ridge members spaced apart from one another. 21.The cap system of claim 19, wherein the ridge members are positionedabout the nut member for engaging a socket wrench.